During manufacturing, an active surface of a semiconductor wafer and laterally separate stacks of semiconductor dice on die locations of the wafer may be encapsulated in a protective material. Individual semiconductor devices comprising the stacked semiconductor dice and a semiconductor die from the wafer may be formed by cutting through the protective material between the die stacks and through the semiconductor wafer along streets between the semiconductor devices to “singulate” the semiconductor devices. Cutting through the semiconductor wafer at the base of a die stack may, in some instances, introduce cracks into or otherwise damage the side surfaces of the resulting semiconductor dice cut from the wafer.
When the semiconductor devices have been separated from one another, side surfaces of each semiconductor die cut from the semiconductor wafer, which may be referred to herein as a “base” semiconductor die for the sake of clarity, may remain exposed during subsequent processing and handling. Specifically, while the die stacks are separated by streets filled with protective material, the base semiconductor dice each comprise wafer material extending under the streets and between adjacent die stacks. Therefore, while the singulation process leaves protective material on the sides of the die stacks, singulation of the wafer leaves wafer material on the sides of the base semiconductor dice exposed.
As a result, the side surfaces of the base semiconductor die may remain exposed as the semiconductor device is transferred to different locations in a facility for further processing of the semiconductor devices, during testing of the semiconductor devices, during assembly of the semiconductor device with higher level packaging and, in some instances, during shipping to and use by a customer. The exposed side surfaces of the base semiconductor die may be damaged during such subsequent processing, testing, assembly and handling, for example, by incidental impacts. In addition, moisture, such as environmental moisture (e.g., humidity) may infiltrate an interface between the protective material at the bottom of the die stack contacting the surface of the base semiconductor die obtained from the semiconductor wafer. The moisture may cause the protective material to detach from the base semiconductor die, such as, for example, through successive expansions and contractions of the protective material during temperature changes.
A semiconductor device produced from singulation of a semiconductor wafer and die stacks may subsequently be physically and electrically attached to an interposer, forming an assembly for connection to higher-level packaging. The die stack and base semiconductor dice may then in some instances be encapsulated by overmolding with the same or another protective material. The interposer undesirably adds to a final height of the assembly, as well as an extra process step and material required by the overmolding of protective material.